1. Field
The present disclosure relates generally to a battery system and, in particular, to a battery system comprised of multiple battery cells. Still more particularly, the present disclosure relates to a method and apparatus for controlling operation of the battery system based on battery cell performance, battery cell temperature, and other selected factors.
2. Background
A battery system may include one or more battery cells. As used herein, a “battery cell” is a single electrochemical device that converts chemical energy into electrical energy to supply a voltage. A battery cell typically includes three components: an anode, a cathode, and an electrolyte. The electrolyte may be, for example, a liquid electrolyte.
Any number of battery cells may be electrically connected to form a series circuit that is configured to provide at least a selected total voltage output. As used herein, “a series circuit” is a circuit in which current can only flow along one path. In a series circuit, the same current goes through every component in the circuit. However, because there is only one path along which the current can flow, opening or breaking a series circuit at any point along the circuit may cause the entire series circuit to stop performing as desired. In other words, an open-circuit condition may be created.
For example, one battery cell in a group of battery cells arranged in a series circuit in a battery system may stop performing as desired, which may cause an opening in the series circuit. The battery cell may be referred to as being in a fault state. The fault state of this battery cell creates an open-circuit condition in the battery system. Because of the open-circuit condition, the battery system may be unable to produce the selected total voltage output, even though other battery cells in the battery system may be operating within selected tolerances. Having a battery system capable of operating to produce an acceptable lower voltage output, even in the presence of one or more battery cells being in a fault state, may be desirable.
Additionally, some currently available battery systems may be unable to properly cool. For example, with some currently available battery systems, the battery cells in the battery system may overheat, which may cause the battery system to stop operating in the desired manner. Having a system capable of accounting for issues that increase battery cell temperatures may be desirable. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.